Updating parameters in subcontroller

I am able to update parameter changes within a controller from the process function as shown in VUppm example in Again.

But how to go about updating a parameter inside a subcontroller ? Here’s my subcontroller class

class PitchbendController : public VSTGUI::DelegationController
	PitchbendController(VSTGUI::IController* icontroller, MainController* mainController) : DelegationController(icontroller) { mainController_ = mainController;			
	IControlListener* getControlListener(VSTGUI::UTF8StringPtr controlTagName) override { return this; }
	CView* verifyView(CView* view, const UIAttributes& attributes, const IUIDescription* description);
	void controlEndEdit(CControl* pControl);
	void valueChanged(VSTGUI::CControl* pControl);
	MainController* mainController_;

And the subcotroller is created using createSubController

if (name == "PitchbendController")
		return new PitchbendController(editor, this);